US2591909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple office voice-frequency line identification system
Assignee: Automatic Electric Laboratories Inc
•
Filing: 1946-05-27
•
Granted: 1952-04-08
•
Expires: 1966-05-27
Abstract
No abstract record available.
Inventors
- 👤 Baker George Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:20
CPC Classifications
H; H04; H04M; H04M15/00; H04M15/08
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2228113A
Cited
US2273165A
Cited
US2373908A
Cited
US2369071A
Cited
US2286445A
Cited
US2369868A
Cited
US2297365A
Cited
US2281508A
Cited
US2283610A
Cited
US2370736A
Cited
US2292977A
Cited
US2265844A
Cited
US2437118A
Cited
US2270246A
Cited
US2252766A
Cited
US2387897A
Cited
US2531637A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-04-08 | 1955-10-08 | 1956-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-04-08 | 1959-10-08 | 1960-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-04-08 | 1963-10-08 | 1964-04-08 | $7700.00 | Window Closed / Lapsed |